


Experimental Omegas

by MapleLoverMattie



Series: Attack on Omegaverse [3]
Category: Shingeki no Kyojin | Attack on Titan
Genre: Alpha/Beta/Omega Dynamics, Alpha/Omega, Anal Sex, Blow Jobs, Fluff, Knotting Dildos, M/M, Mating Cycles/In Heat, Smut
Language: English
Status: Completed
Published: 2015-01-22
Updated: 2015-01-22
Packaged: 2018-03-08 14:48:12
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 8,363
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/3213077
Author URL: https://archiveofourown.org/users/MapleLoverMattie/pseuds/MapleLoverMattie
Summary: <blockquote class="userstuff">
              <p>A short oneshot about Eren and Armin before they met their mates.  This is set before both The Adventures of Armin the Omega and Bonding Adventures with Eren<br/>Omegaverse AU<br/>Ever wonder how Eren and Armin spent their heats as fellow Omegas.  This short story should hopefully clear things up.<br/>*recently edited so enjoy the changes</p>
            </blockquote>





	Experimental Omegas

**Author's Note:**

> Hey guys, I'm sorry I sort of dropped off the face of the Earth. This last month has been really stressful for me. I had a hard time writing after some of the things that happened over the holiday season, but I'm okay now. So here it the oneshot I mentioned that I wanted to write.
> 
> Feel free to check out my tumblr attackonomegaverse for more omegeverse fics and info or if you want to make a request or something.
> 
> *Edit: I have edited this chapter so I hope that new and old readers like the new changes. I felt like it was missing things so I added more to the chapter (close to 4000 words more)

Armin still couldn’t figure out how he ended up like this every three months. Sure it had been happening since he and Eren had been sixteen, but that still didn’t explain why it happened. Especially since that was five years in the past, they were adults now. Not hormonal teenagers. Despite his complete lack of understanding, Armin still found himself responding to Eren’s text message.

Yes, I’m close to my heat too.  
Will we be spending our heats  
together again?

The first time they had spent their heats together it was because Eren had presented over at Armin’s house. They had been planning the sleepover all week, since school was letting out for the summer and they finally had time to hang out. Armin always needed to study somewhere quiet so he told Eren that it was best to not hang out during finals week. He had no idea how easy high school finals would be compared to college finals, but at that time it didn’t matter. 

Eren had recently turned sixteen and hadn’t presented yet, much to the uneasiness of his parents. Armin had presented as an Omega back when he was thirteen, and most of their classmates had already presented. Mikasa had presented as an Alpha when she was fifteen, something that had come as no surprise with how protective she was over Armin and Eren. Eren was the mystery of the school. No one could tell what he would present as, but the most common vote had been towards Beta since it had taken him so long to present.

Needless to say, due to all his studying Armin hadn’t paid any attention to his body’s cues that he was getting close to his heat, and by the time he had figured it out Eren had already been at his house and sleeping next to him on the bed. Armin had woken up covered in sweat and feeling like his body was on fire, and he knew instantly what was wrong. He hadn’t even had to wait for the painful cramps to hit him before he knew that he was in the early stages of his heat.

Armin had looked over towards Eren only to notice that his best friend wasn’t sleeping like the dead as was his usual habit. Eren had curled up into a ball and was shaking slightly. The movement had just enough force that Armin could feel it traveling through the mattress. Maybe he’s having a bad dream Armin thought as he instinctively reached out to shake his best friend’s shoulder. Eren woke with a jolt, that startled Armin, but he was determined to help his friend regardless of how much discomfort he was feeling.

Eren turned to face Armin confused, why did he feel so warm and why did everything hurt he wondered blinking blearily at Armin. The first thing he noticed in the faint light was that Armin was panting slightly and he had a grimace on his usually cheery face. The second thing he noticed was that Armin smelled really sweet and his normal scent was thicker. The third and final thing was that he could smell himself, and he seemed to be giving off a similar scent, and that could only mean one thing. He had presented finally. Eren was an Omega, and he was experiencing his first heat at his best friend’s house while Armin was also in heat.

“Eren, are you alright,” Armin asked quietly, somehow managing to keep the needy tone out of his voice. Eren just blinked up and him a few more times. This unnerved Armin, but he couldn’t let the strangeness of Eren’s behavior detour him. “Did you have another nightmare?” Armin managed to ask before wincing in pain as a particularly painful cramp wracked through his abdomen. 

Eren shook his head, “I’m fine. I didn’t have a nightmare. I think... Armin… I think I might be going into heat,” Eren said barely above a whisper. He really didn’t know how to address the situation, and from the way Armin looked away neither did he.

“Eren, I think we need to call your dad. He should come get you and take you home. Since it took you so long to present, your heat is probably going to be brutal…,” Armin trailed off, it was kind of embarrassing talking about his best friend going into heat like that.

“NO!!! Don’t, please don’t call my dad,” Eren begged, he didn’t want to be looked down on by Grisha. His father had concluded that Eren was going to be an Alpha, since there was no way that Eren could be anything but that with how vehemently he fought authority.

It would have been different if Eren’s mom was still around, but she had died after a long battle with cancer the year before. Grisha had gone into a depression and more often than not he spent his nights at work leaving Eren to fend for himself. When he wasn’t at work he was home in a drunken rage. More times than not, Eren had to go hide in his bedroom to avoid his father’s angry fists.

“Okay, okay. I won’t call him, but what are you going to do, Eren?” Armin asked worry creeping into his voice.

“Can I please stay here? Just until it’s over… and then I’ll go home. Please…,” Eren begged of Armin. He knew that his best friend wouldn’t be able to refuse him.

Armin caved easily, “Okay, but I need to tell Grandpa. So he can bring us food. I’ll make him promise not to tell anyone.” Armin was already struggling to get up out of his bed. He knew that he still had a little while before his mind would be consumed by the desire to be filled and knotted so he had to make use of it.

Armin had gone and told his grandfather everything and he had been reassured that Grisha wouldn’t find out until Eren told him. Armin had also asked if it would possible for his grandfather to go and get Eren something to easy his heat, all with a dark blush on his face as he avoided eye contact. Armin wasn’t entirely sure if it was sanitary to share the same things with Eren, but he didn’t want his friend to suffer like he did when he first presented. His grandfather had said yes, and had shooed him back up to his room so that he could be there to help Eren.

That had been so long ago and Armin remembered how embarrassed both of them had been. Neither Eren nor he could bare to look the other in the eye for a week afterwards. Armin had created a small nest on the floor while Eren had taken over the bed during that week. While it had been strange at first as the years went by Armin had gotten used to Eren messaging him when he got close to his heat. It didn’t bother either of them anymore as after their first few heats together they had decided to experiment in an attempt to satisfy their urge to mate. It never lasted long, since both their bodies wanted to be knotted, but it was better than just using their hands and toys. 

Armin felt his phone vibrate in his hand and he looked down at it, knowing that it was Eren responding to his question.

Yuppers i wanna try somthng  
new u should come over 2nite  
roomie w/ his girl

Armin sighed, he really hated it when Eren sent texts. He couldn’t figure out why Eren felt the need to riddle his messages with so much text lingo or why he used so many shortened words. Armin was pretty sure that it was just Eren’s laziness taken hold, but it didn’t mean that he had to like seeing the messages like that. Nevertheless, Armin messaged back before he packed a small bag with the things he would need over the next week.

Okay, on my way over. Can you let  
Mikasa know that we will be busy  
for the next week, please?

He didn’t need to check his phone again, he knew that Eren would take care of telling Mikasa. The female Alpha would probably make some crude comment about the two of them spending their heats together again. Armin knew that Mikasa meant well, but it was still irksome when she would try and pressure him and Eren to find mates. It wasn’t like they weren’t trying, but Armin wasn’t going to settle for second-best and Eren was too stubborn for any of the Alphas they had met so far.

That was the real reason that they spent their heats together. It was getting too difficult to spend their heats alone as their bodies demanded that they find a mate and reproduce. Most of the Omegas their ages had already found their mates years before, so if they didn’t already have children they had a mate to be there for them when they went into heat. Armin hated his biology at those times. The longer he went without a mate the more demanding and painful his heats were becoming. He had never considered taking suppressants because of the possible risks to his fertility, but sometimes he wished that he had taken them just because of the nature of his heats. 

Thankfully, he had Eren. Eren didn’t want a mate unless he met someone that could deal with his stubborn nature, and Armin gave him props for that. Although, recently Eren had been talking about an Alpha that was helping to tutor him with his Criminal Justice class and the developing crush that he had for the man. Armin was really happy for him and he wished Eren luck with the man, but that didn’t mean that Eren was ready to spend his heat alone as he repeatedly told Armin.

Armin soon found himself at Eren’s dorm room and he laughed at all the stupid door decorations that covered it. Sasha had spent a lot of time coloring various pictures of food and taping them to the wooden surface. Armin could just barely see the original door decs that said Eren and Connie’s names on them. Eren must have pulled them all off recently since the last time he had seen the door it had tons of pictures of sushi on it and now it was breakfast foods. 

Armin didn’t even knock before he entered Eren’s room, he knew that the door would be unlocked and that Eren was expecting him. He found Eren curled up on his bed with is laptop rested between his crossed legs. Eren looked up when Armin entered the room and smiled before he closed his laptop and placed it down on his bed.

Armin sighed, he felt like he was walking into a hazard zone. Eren’s room looked like a tornado had gone through it specifically targeting his blankets and clothes. The bunk beds that he shared with Connie had been turned into what Eren liked to call his cave. A spare sheet had been tucked up underneath Connie’s mattress so that Eren’s lower bunk would be enclosed when Eren removed the frog shaped bag clip he used to pin the sheet back. He had already created a nest on the lower bunk with the rest of the blankets and pillows he possessed, and Armin had to concede that it looked very inviting and he was slightly jealous. He wasn’t able to do that in his room since his roommate, Marco, and he had the room separated by sides. Maybe he would talk to Marco about rearranging the room after he ended his heat. Then again that meant that he would have to get down from his lofted bed and Armin liked sleeping close to the ceiling so he could look down on anyone that entered his room. 

“… Earth to Armin,” Eren said, noticing that his words were finally noticed by his best friend.

“Oh, sorry. I got to thinking about how nice your nest looked and got a bit jealous,” Armin said as a light blush covered his cheeks. He dropped his bag down on the messy floor and moved to sit down in the uncomfortable desk chair that was surprisingly free of clutter.

“Yeah, I know. Isn’t it awesome? It took me a week to convince Connie to bunk the beds and as soon as we did I started on my nest. I only got it perfect a few hours ago,” Eren gushed. His Omega instincts were pleased knowing that there was another Omega jealous of his nest. This was the only time that Eren would indulge his instincts so it was a nice change from constantly fighting himself and others.

Eren didn’t like to allow his instincts to rule his life, he didn’t want to be seen as a weak Omega. He wanted to prove to all the Alphas that looked down on him because of his nature that he wasn’t weak. He didn’t belittle those the listened to their instincts, he knew that Armin relied on his instincts all the time and that was fine with him. However, he wasn’t Armin so he would behave how he wanted. Eren was pretty sure that his desire to suppress his instincts on a regular basis probably had more to do with how his father looked down on him for being an Omega when he should have been an Alpha then how other Alphas treated him, but Eren didn’t really care. He wanted to be independent and if the Alphas that he met didn’t like how he behaved then he didn’t need their approval. 

“Anyways, so how’s Marco? Is horse-face still following him around like a lovesick puppy?” Eren asked suddenly changing the topic. He really didn’t like thinking about depressing things right before his heat.

“Marco’s good, I think he synced up with us though. He is pre-heat right now as well, so it’s a good thing that I come and stay with you during my heat. Plus, Jean is hanging around Marco a lot more than he usually does, but who can blame him? Marco did agree to spend his heat with him,” Armin said casually trying not to put as much emphasis on the details that he was telling Eren. Nevertheless, Eren still understood the implications of Marco allowing Jean to join him during his heat.

“He what!? I told him that horse-face was no good for him. Jean might be an Alpha, but geez can’t Marco see that he is a total asshole. Ugh, what is he thinking? I have half a mind to go ask him that myself, but I don’t want to see the horse,” Eren raged overdramatically. Eren really didn’t like Jean, he barely tolerated him for his friend’s sake.

Eren and Jean had never really seen eye to eye, always butting heads on stupid things, but after Eren returned to school in the fall after presenting as an Omega things had gotten worse. Jean had teased him about being an Omega incessantly for about a month, until Eren had finally tackled him to the ground and punched him in the face. Granted Eren had been complaining about how Alphas were all talk and no action, how they were all stupid muscle heads, and how they wouldn’t last a day without an Omega looking out for them. Nevertheless, Jean’s retort about Omegas being useless and only go for fucking had been over the top, triggering Eren’s uncontrollable rage. Jean had stopped teasing him about his nature after that, but Eren still didn’t forgive him for that. He knew that Jean hadn’t really meant all of the things he had said, but the words had still hurt Eren. Coupled with the fact that Jean’s words had mirrored the words of his own father had made the impact much worse. Jean had apologized numerous times since then and Eren left it at that, instead focusing his time and energy on his schoolwork and favorite pastimes.

“Eren… you know that Marco loves Jean and vice versa so just let it go. Just because Jean accidentally insulted you doesn’t make him an asshole. You had it coming to you when you started yelling about how shitty Alphas are in the middle of the hallway. You need to let it go, especially since that happened in like 11th grade and both of you have matured since then,” Armin said with an exasperated sigh. When he saw Eren’s furrowed brows, Armin couldn’t help but think, well maybe only one of you has matured. Armin hadn’t been there when the fight had occurred, since he had been in the library returning some books, but word had travelled fast and he had heard about it long before his saw Eren. Eren had refused to tell him what had really happened so Armin had been forced to believe what he had heard from others.

“No more talk about the horse, my room my rules,” Eren said suddenly breaking the slightly awkward silence he had created. He really wanted to talk about something else, and he knew the best way to change the topic. “So what did you bring with you this time? Anything new, or just the same toys from last time?” Eren asked his curiosity getting the best of him when he eyes landed on the bag at Armin’s feet.

Armin face turned a bright red and he looked around the room as a way to avoid eye contact with his best friend. Armin hated it when Eren asked him about his toys. He knew that it was stupid to be embarrassed since they both had them, but he still blushed every time Eren brought them up. “Just clothes and stuff,” he mumbled as he caught his lower lip between his teeth and began to chew on the slightly chapped skin he found there.

“What kind of stuff? You know if you don’t tell me I will go through your bag, I’ve done it before,” Eren threatened good-naturedly. Armin’s blush had progressed passed just his cheeks and now his ears where a bright red to match. Eren could see the color creeping down his best friend’s neck and he grinned triumphantly. 

“Just the usual stuff,” Armin muttered again shooting Eren a glare as warning that if he touched his bag Armin would kick his skinny little ass. It didn’t matter if Eren outweighed him by a good 15 pounds and was much stronger than he was, Armin would still give it his all to defend his bag.

“Fine, fine. I will find out soon enough anyway. So how close do you think you are?” Eren pouted, but changed the subject much to Armin’s relief. Eren really wasn’t in the mood to roughhouse with his best friend, the mild cramps that he was feeling in addition to the slight tenderness of his chest and hips was a major influence on that idea. 

“I don’t know, I have some cramps, my body is sore, and a light fever, but it’s nothing that a mild painkiller couldn’t fix. I saw a few Alphas follow me with their eyes on my way here, so that means I’m giving off a strong enough heat scent to attract their attention. What about you?” 

“I’m thinking that I have a few more hours or so. I can feel my body heating up so I’m getting close,” Eren said with a shrug as he scooted to one side of his bed and patted the empty spot next to him as a means of asking Armin to join him on the bed. Eren was suddenly in the mood to cuddle and take a nap, and who better to join him that his best friend and fellow Omega, Armin.

Armin quirked an eyebrow, did Eren think he was a cat or something that would respond to something like that. Granted the bed did look comfy and Armin was tired. He wouldn’t mind taking a nap with Eren curled up in the nest. Who was he kidding, Armin thought as he scrambled over to the bed and flopped down next to his best friend, there was no way he was going to choose the crappy wooden chair over Eren’s plush nest.

Armin tucked himself up against Eren side and watched as Eren browsed through his tumblr feed on his phone. He could feel his eyelids getting heavier as the minutes passed and he stifled a yawn against Eren’s side. 

“Naptime?” Eren asked with a light chuckle and Armin nodded wrapping his arms around his best friend’s waist. “Do you want your blanket?” Eren asked again causing Armin to frown, followed by a vigorous nodding as he let Eren go long enough to grab the soft blue blanket that he had brought with him. 

Eren laid back down and draped the blanket over both of them, a few seconds after he removed the clip and allowed the sheet to cover the front of his bed completely. He figured it was in his best interest to take a nap while he could. It was going to be a long week.

* * * *

Armin woke up to Eren writhing on the bed next to him. He could tell that his best friend was still sleeping, but the prominent erection that pressed against Armin’s stomach suggested that it wouldn’t be for much longer. Armin could already feel his heat settling in fully, as his stomach cramped painfully and his cock twitched between his legs.

Armin reached underneath the waistband of his sweatpants and boxers to check how far his heat had progressed since he had fallen asleep. He wasn’t surprised to feel a bit of slick trickle out of his hole. That was what got Armin moving faster, even though his body wanted him to just lay there and do nothing. Armin slid off the bed and dug in his bag for a few seconds until his fingers closed around a familiar object.

Armin pulled the dark blue butt plug out of his bag and quickly slipped down his pants and boxers. He leaned forward and slid a finger into his slicked up hole just to test how ready he was. He didn’t want to hurt himself by pushing the plug in his needy hole without some semblance of preparation. After a minute or so he slipped another finger in and he couldn’t hold back the pleasured moan that passed his lips. His breath was coming in pants and he arched his back when his nimble fingers brushed his prostate. Armin felt his body produce more slick and he pulled his fingers out with a needy whine, before he slowly pressed the butt plug into his hole until it was flush with his ass.

A few more moans passed Armin’s lips before he could collect himself enough to think. Armin felt himself shiver as the tendrils of pleasure travelled up his spine. He could hear Eren whimpering in his restless sleep and Armin crawled back towards the bed dragging his bag with him so that he could reach it by leaning off the bed. He stood up slowly, allowing his body to adjust to the familiar plug in his ass. He felt himself shiver again when the plug shifted slightly with his movement, and Armin welcomed the pleasant shiver while he was still cognitive. Armin climbed back on the bed and let out a loud moan when the tip of the plug managed to brush against his prostate accidentally.

Armin laid down next to Eren and noticed that he had kicked off the blanket with all his writhing. Armin could tell that Eren was farther into his heat than he was and it baffled him that Eren hadn’t woken up yet. Nevertheless, that didn’t stop him from reaching forward and pulling down Eren’s sweaty shorts. Armin came face to face with Eren’s erection and wasn’t surprised to see that it was already leaking pre-come; Eren usually had very powerful heats and they had only gotten worse as they got older. Armin wrapped his fingers around his best friend’s leaking cock and watched as Eren arched off of the bed with a loud moan.

Armin stroked Eren’s erection a few times before he leaned forward and wrapped his pink lips around it. Armin couldn’t deny the claim that he liked giving head. He had discovered his love of cock during his second heat spent with Eren. He had just jerked himself until he came when he caught a glance of Eren with his fingers of one had stuffed in his ass and the other hand rolling his pert nipple between his nimble fingers. Eren’s cock had been standing at full attention and seemed to be beckoning Armin to come closer so that’s what he had done. Armin had crawled between Eren’s spread legs and had licked a stripe up the underside of his best friend’s cock before engulfing the leaking cock in his warm mouth. As they spent more heats together Armin had made it a tradition to get Eren off with his mouth at least once when he could still think. Armin loved the heaviness of a hard cock on his tongue as it slid in and out of his mouth. He could get off just from watching the expression on Eren’s face as he sucked him off; Armin couldn’t find a negative side to blow jobs since he didn’t even mind the taste of cum. 

Armin hummed around Eren’s cock when he heard more moans coming from Eren, and he knew the exact moment that Eren woke up. His best friend had bucked his hips upwards, pushing his erection deeper into Armin’s mouth. Armin pressed a hand down on Eren’s hips as a reminder that he needed to stay still. Armin had Eren’s cock practically down his throat by then, when he felt it brush the back of his throat gave a strong suck and hummed again. He felt Eren’s erection twitch against his tongue and Armin slipped his fingers into Eren’s boxers and began to fondle his balls. It only took a few more bobs of his head before he felt Eren come undone. Armin pulled back a little bit, but tightened his lips around the head of Eren’s cock and swallowed as quickly as he could. He didn’t want a single drop of Eren’s cum to escape his mouth.

Eren’s body arched upward as a loud keen slipped past his lips, he couldn’t go too far as Armin had a sturdy hold of his hips. He loved how Armin always woke him up with a blow job. It took the edge off his heat momentarily and it allowed him to focus his mind long enough to help relieve Armin. Eren’s body fell back onto the bed and his breath came in pants as he struggled to catch his breath from the sudden orgasm. He could feel his slick starting to trickle from his empty hole, but Eren paid that no mind. He would have plenty of time to deal with that after he helped Armin get off.

Armin looked up from Eren’s crotch and smiled. He could still taste the slight bitterness of Eren’s cum in his mouth and it made him want to moan wantonly. Armin licked his lips to make sure that he didn’t have any cum on them before he swallowed again. “Was that good for you?” he teased as he rolled over onto his back and stretched out on the bed next to Eren. One of his hands had already slid down to rub against his straining erection. 

“Yeah—,” Eren panted out. He could already feel himself getting excited again, being in heat was annoying like that. Armin noticed as well since he had rolled onto his side and had pressed himself against Eren’s side so he could grind his erection against Eren’s thigh. Eren could feel Armin’s hot, little panting breaths against his arm as he best friend humped his leg. 

Armin knew he was already too far gone to control his voice. He could hear himself moaning and whimpering when he couldn’t get enough friction from rubbing against Eren’s thigh. He rolled his hips and he gasped when he felt his plug press against his prostate. It felt heavenly and Armin could feel more pre-come leak from his erection and onto his hand. It made it easier for his hand to slide up and down, Armin relished in the slight increase in speed that the slickness allowed. His breathing was becoming ragged and he had stopped trying to think about anything besides his own pleasure as his hand continued to pump his straining erection. 

Eren was better off than his best friend, but that was only because he had come recently but even that small release could only help to clear his mind so long. He wanted to revel in the small reprieve from his heat as long as he could though. It was even more beneficial when he turned his head and buried his nose in one of the pillows he had sprayed with artificial Alpha scent. His mind didn’t feel so cloudy and he managed to convince his instincts that an Alpha had been the one to get him off. He pushed himself up so that he was leaning back on his forearms as he looked down at Armin.

Armin had lost his pants at some point and his boxers were pushed off his hips and clung to his thighs as he palmed his erection and rutted against Eren’s leg. He felt Eren move and he let out a pitiful whine to convey his neediness. He didn’t want his best friend to pull away, but he couldn’t get his mouth to work right. Suddenly a pillow was shoved in his face and Armin got a strong whiff of Alpha scent and he was coming into his hand. He was pretty sure that he screamed, but he was too far gone to care. His instincts were appeased by the scent of an Alpha even if it was made in a factory. 

“Thanks,” Armin gasped out as he tried to relax his body. His relief was temporary as his Omega instincts demanded that he be knotted, even the slight stretch of the butt plug wasn’t enough to stave of that desire for long. With the added slick that his body had produced during his orgasm, it was much easier for the plug to shift around and his hole felt much looser. Armin had a passing thought that he would need to look into getting a larger plug before his next heat, but at that moment he would have to make do with what he had on hand. 

“You should try to go back to sleep, we still have a few more hours before we will be insatiable,” Eren suggested, his voice was muffled by the pillow that he was burying his face in.

“You’re right,” Armin said with a groan, curling up around the pillow Eren had given him. He didn’t remove the plug from his ass as he knew that he would only be needier if he didn’t have it when he woke again. He allowed the artificial Alpha scent to help his body relax, Armin was so happy when he happened across an advertisement for it in the 12th grade. It had made it easier to get though their heats by allowing their Omega instincts to relax temporarily without the actual presence of an Alpha. Armin took another good whiff of the strong Alpha scent and allowed it to help lull him to sleep.

* * * *

Armin was pretty sure that it was day two or three, he couldn’t be sure. All he knew was his heat was wreaking havoc on his body and he wasn’t even through the worst of it. Which reminded him that he really need to get off again. He went to reach for his leaking erection only to find that he couldn’t move his arms. He let out a frustrated cry and he jerked his arms trying to free them from whatever was restraining them. Armin had never been restrained before and he really couldn’t tell if he liked it. At the moment all he wanted to do was get free so he could satisfy the uncontrollable heat that was ravaging his mind and body. 

Thankfully, Armin discovered that his legs were free and able to be moved so he bent his knees and arched his body upwards and then ground his ass back down on the mattress of the bed. He was pleased to discover that he still had his butt plug in, when his movement pressed it against his prostate firmly, Armin tried to hold his positon as he rutted his ass down on the bed. The plug continued to abuse his prostate and Armin couldn’t help but whimper and whine when it wasn’t quite enough to satisfy his need to be filled. Just as he was about to arch his hips upwards again, Armin felt a firm hand pressing him back down against the mattress. 

Armin opened his eyes and saw Eren crouching over him with a mischievous smile on his face. He had a hand resting on Armin’s hip, holding him down so that he couldn’t buck upwards like he so desperately wanted and needed. Eren leaned forward and pressed a kiss against Armin’s slightly parted lips, before pulling back resting his forehead next to Armin’s ear. “Do you like your surprise?” Eren asked in a whisper that seemed like a caress to Armin’s overheated skin. 

“Wh-what?” Armin managed to ask. He couldn’t control his body, despite Eren’s firm hold Armin still tried to arch upwards against him futilely trying to get some form of friction. 

“You can’t touch yourself, you’re going to be completely at my mercy. That’s the surprise, you said you wanted to try something more exciting this time. Don’t worry though, I have your favorite knotting toy ready so after I fuck you until you come, I can fill you with the fake knot just like you love.” Eren continued to hold Armin down, preventing him from getting the friction he so desired much to Armin’s displeasure. Eren smirked when he heard his best friend’s whimpers. 

Eren knew that it was slightly odd that as an Omega he took pleasure in being so domineering. He had learned that he loved topping during his first year of college when he had given into Armin’s pleading voice. Eren had taken the initiative to pin his best friend down to the mattress as he fucked him into oblivion. Eren had managed to maintain just enough control of his senses to remember to pull out before he came. He had fulfilled Armin’s need like that many times during that heat and it was something they did on a regular basis now when they were together. Eren had remembered to do research about whether or not an Omega could get another Omega pregnant, but he hadn’t found much information on the subject. With only inconclusive results, Armin and he had agreed that it was for the best that they made sure not to come while inside the other.

Armin could only nod since his tongue felt like it was made of lead and he couldn’t find the ability to speak, everything that Eren suggested sounded so wonderfully good. Armin couldn’t even think about anything besides being filled and knotted. He wanted to have an Alpha draped over his sweaty back pounding into his slick hole, knotting him, and filling him with his hot cum. “Please?” Armin begged before he even realized that he could speak. 

Eren didn’t wait for his best friend to ask again before he was suddenly pulling the butt plug out of Armin’s needy hole and pressing his own leaking erection into the slick hole. Armin’s moans were music to his ears as he pounded into his friend. They had been fucking each other for a few years now, and even though it was never enough it took the edge off longer than just jerking each other off or giving each other a blow job. Eren was letting his own moans slip passed his lips as he thrust into Armin’s hole as deeply as he could. He knew where Armin’s prostate was by memory now and it wasn’t difficult to hit it spot on with each thrust. 

Eren groaned it felt amazing having his cock surround by the wet, heat of his best friend’s hole. Eren clenched his jaw tightly as he tried to stave off his orgasm as long as he could. He thought fucking Armin felt almost as good as getting fucked by his best friend. Eren wrapped the fingers of one of his hands around Armin’s leaking erection and began to pump in time with his thrusts. He knew that his cock wasn’t quite thick enough or long enough to get his friend off on its own.

Armin was delirious with pleasure and he couldn’t contain his moans, he was probably begging for Eren to give him more and to go harder, but his mind was muddled and he really didn’t have a good handle on reality at that particular moment. Armin could feel that he was getting close, the familiar ball of heat was pooling in his stomach and he couldn’t stave off his orgasm if he had wanted to. His hole clenched down on Eren’s cock as he came hard, screaming out Eren’s name. He could fell Eren’s hand continue to pump his erection as he came to string out his orgasm, but he couldn’t even raise a hand to stop him as his arms were still tied above his head. Eren pulled out and came against Armin’s chest, his come mixing with Armin’s. Armin whined and Eren was reminded that he hadn’t fulfilled his promise of filling Armin with his favorite toy. 

Eren reached out and wrapped his fingers around the familiar toy as he sat back and lined it up with Armin’s abused hole. He didn’t give his best friend any warning before he shoved the toy in and began to squeeze the pump to form the artificial knot that Armin was craving. In a matter of seconds the knotting toy was at full size and Armin was coming again at the feeling of being filled so full. Armin’s looked absolutely wrecked with the toy sticking out of his ass and come splattered all over his chest. 

“Eren?” Armin panted out. His voice was scratchy from moaning and screaming so much and it would only get worse. 

Eren looked down at Armin and smiled, “Yeah, Ar?”

Armin just jerked his arms and whined. Eren chuckled and shook his head, “I’m sorry Ar, but I’m not done with you yet.” 

Eren truly wasn’t done with his best friend. He still had a few more ideas that would be more fun if Armin couldn’t stop him. The first one was to deny Armin his orgasm, granted it would feel like torture to his heat minded best friend, but Eren knew that when Armin finally got his release it would feel heavenly and it would hopefully help to relieve his heat longer than a normal orgasm did. The other idea that Eren had was to fuck himself using Armin’s restrained body. He would still be in control of the situation, while getting both of them off at the same time. They still had plenty of time left to determine what would take place since they were both still in the middle of their heat.

Armin whimpered, but relented. He knew that once Eren got an idea in his head there was no deterring him until he had completed his subconscious mission. Armin closed his eyes and allowed his body to temporarily relax due to the artificial knot that was filling him. He felt his body relaxing and drifted off again.

* * * *

It was probably day five of their heat, Armin deduced that based on how exhausted he felt and the slight decrease in neediness. He could still feel his heat running rampant, but he was beginning to feel like a human. If he predicted right, both of them would be through their heat by the end of the night or early morning. Those thoughts were all well and good, but they did nothing to relieve him of the straining erection that throbbed between his legs. 

Eren had made good on his promise and had shown Armin just how pleasurable being restrained could be, but he was glad to have his arms free again. He knew that his shoulders would be screaming by the time his heat dissipated completely, until then Armin was going to take advantage of his new found freedom.

Eren was curled up on his side with his face buried in the Alpha scented pillow as he attempted to jerk himself off. Armin took notice of this and decided that it was time for him to repay his best friend for the wonderful treatment of his needs. Armin also noticed the dark green end of Eren’s own knotting toy. It was laying on the messy sheets just waiting to be used to fill the needy hole of an Omega. Armin reached out his fingers and grabbed it before scooting closer to his best friend.

Eren didn’t even take notice of his surroundings, he was so close. He just needed to come and he would feel temporary relief. Eren’s instincts were screaming at him, telling him that he need to be filled to the brim to feel relief, but he didn’t know where he had left his knotting toy. It was probably hidden under a blanket or something.

Armin watched as his friend removed one of his hands from his cock and moved to shove his fingers into his needy and dripping hole. Armin’s hand instinctively shot out and prevented his best friend from doing what he wanted to do. Armin’s free hand was still wrapped around the knotting toy as he brought it forward and began to circle the head around Eren’s hole. 

Eren turned his head and saw Armin; however, his attention was more focused on the feeling of a toy gently pressing into his opening. It wasn’t enough. Eren moaned, he needed to be filled. He didn’t want to be teased any longer.

“Ar, please—?” Eren begged. He rolled over onto his stomach and raised his hips in the air as he tried to coax Armin to do his bidding.

It was a truly lovely sight, Armin thought as he continued to tease Eren for a few more seconds before he suddenly shoved the large toy inside of Eren’s slick drenched hole. Eren screamed, it felt amazing, but it still wasn’t enough. He needed to be knotted.

Armin began to fuck Eren with his toy, periodically using the pump to gradually increase the fake knot as another way to tease his best friend. Suddenly, Armin was struck with a great idea.

He stopped what he was doing and laid back on the bed before he called out to Eren. “Eren, come here. I want you to suck me off while I fuck you with your toy,” Armin said unabashedly. He lost all traces of innocence once he was in the throes of heat. Eren obediently did as Armin asked and he knelt over his best friend. He head was hanging above Armin’s straining erection while is ass was trembling over his best friend’s face.

Once they were in their new positions, Armin immediately continued with his previous task. It took Armin thrusting his hips upwards a few times before Eren finally realized that he wasn’t doing his job. He didn’t waste any time. Eren wrapped his lips around Armin’s cock and began to bob his head enthusiastically. He didn’t particularly like giving blow jobs, but he wasn’t above doing what his partner asked of him. 

Eren’s moans were muffled by the cock in his mouth, and the vibrations felt absolutely amazing to Armin. He was pretty sure that this was the best blow job he had ever gotten from Eren, even if his best friend had to pull away every time Armin hit his prostate with the toy. The toy was almost fully knotted in Eren’s ass so Armin did the only thing he could think of to send his friend over the edge.

Armin raised his head off the bed and leaned forward just enough to wrap his own lips around Eren’s leaking erection. The sudden heat combined with Armin pressing the pump rapidly so that the toy fully knotted and abused Eren’s prostate had his best friend coming with the most violent orgasm Armin had ever seen. Armin wasn’t able to maintain the suction that he needed to swallow Eren’s cum when Eren’s body suddenly jolted upwards he collapsed on top of his best friend.

“LEEVVII!!!” Eren screamed out when the knotting toy struck his prostate and filled him completely. Eren was in such a state of euphoria that he hadn’t even noticed what name he had called out, but Armin had. He was definitely going to probe for information once their heat was over. 

Armin slowly rolled Eren off of him and back onto the bed so that he could finish where Eren had left off. With a few pumps of his hand Armin was coming himself and he relaxed back on the bed himself as he allowed exhaustion to take over and drag him off to dreamland.

* * * *

Armin woke up and all he could feel was sore muscles he groaned in pain as he tried to untangle himself from Eren. Eren was sleeping with his head on Armin’s chest and his arms wrapped around Armin’s waist effectively pinning him. Armin raised a hand and scrubbed it over his face as he tried to wipe the sleep from his eyes. He had no clue what time it was or what day it was. The last time he had woken up Eren had been fucking him into the mattress with his favorite toy.

Armin felt a blush raise on his cheeks at the thought of what had transpired after that. Armin had turned to tables on his best friend shortly after that and had pound into Eren as he presented Armin with his pretty little ass. Armin had fucked Eren until he had come. Eren had collapsed against the bed and Armin had pulled out only to shoot his load all over Eren’s ass. He had shoved Eren’s butt plug into his needy hole and proceeded to fuck himself with his own knotting toy until he came again when his toy reached its largest size. 

Armin should have felt embarrassed, but he had become immune to the situation after years of repetition. Plus this was all practice for when he met his mate, Armin thought to himself. He wouldn’t be one of those inexperienced Omega’s that couldn’t suck dick. Just the thought of sucking his future mate’s cock had the last tendrils of his heat turning him on. He slid down and out of Eren’s arms and repeated the same actions he had done when their heat had first started.

Sometime later, after both Omegas had come and rolled out of bed. They had somehow managed to drag their sore bodies to the bathroom where they proceeded to share a shower. They had tried showing separately a few times, but that only took more time and it was easier for someone else to help when they was trying to wash all the cum, slick, and sweat off of their bodies. Once they were showered they pulled the sheets off the bed and threw them into the hamper to be washed later that day.

Armin was digging in his bag for the clean sheets he had brought with him when he was suddenly reminded of the name Eren had called out during his orgasm. Armin had noticed that every time that Eren had come after that he had called out the name in some way, usually it was just barely a whisper as his best friend moaned his release.

“So who is Levi?” Armin asked, handing the new sheets to Eren.

Eren’s cheeks turned a dark shade of red upon hearing the name. “What do you mean?” Eren asked trying to nonchalantly avoid the question.

“You called out the name Levi every time you came, so I was just curious. Is that the name of the Alpha that is tutoring you?” Armin asked. He wasn’t ready to let the topic drop just yet.

Eren’s blush travelled to his ears and he sputtered, “He’s—he’s … he’s nobody…don’t worry about it.” He quickly busied his hands with making the bed.

Armin just smiled, Eren’s reaction was enough of an answer for him. “Don’t worry I won’t tell Mikasa,” Armin promised as he climbed onto the newly made bed. “Now get up here and take another nap with me.”

Eren sighed in relief as he climb back into bed and allowed Armin to curl up against his side. He was so lost in thought that he didn’t notice when his best friend fell asleep. Eren’s mind was filled with imaging thoughts of Levi being the one to help him relieve his heat instead of Armin. Eren was surprised by the graphic images and shook his head to clear it. Levi wasn’t anything but a tutor to him, right? Wasn’t it just a silly little crush on Eren’s part? Levi was the only Alpha that Eren had ever been able to tolerate for extended periods of time, but that didn’t mean anything. Eren didn’t know how he was going to face his tutor when he next saw him, but he did know that it was better to just give up on his crush before he got hurt. There was no way that Levi felt the same way as he did, Eren told himself as he burrowed under the blankets and focused on getting some sleep.

**Author's Note:**

> So I hope everyone liked it. I am going to try and work on the next chapter of The Adventures of Armin the Omega tomorrow and then I'm going to talk to creoleereri about doing another chapter for Bonding Adventures with Eren. Feel free to leave comments or suggestions. I live for them and they make me write faster. ( well I'd like to believe that, but who knows)


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